README

#+TITLE: swankr: SWANK (and SLIME) for R
#+AUTHOR: Christophe Rhodes
#+EMAIL: csr21@cantab.net
* Introduction
This is swankr, an implementation of the swank[fn:1] protocol for
R[fn:2]. While the coverage of swank protocol functions is
currently limited, enough is implemented for swankr to be useful: at
the very minimum, it can be used to develop and extend itself.
** Relationship with ESS
Emacs Speaks Statistics[fn:3] provides an interaction mode for R
(among other statistical software packages), including an interface
to R's toplevel, and keybindings to send input to R, to look up
documentation, and so on. Where it differs most noticeably from
swankr is in the level of integration of various facilities with
emacs: ESS uses the browser() debugger, whereas swankr provides its
own debugger, sldb; swankr provides a custom REPL with hooks for
common commands; and so on. On the other hand, ESS is mature,
feature-rich software, while swankr is only a little more advanced
than a proof-of-concept. For Lisp programmers, perhaps the most
useful analogy is to say that swankr intends to be to ESS what
SLIME is to ILISP. At present, ESS mode remains active in R source
buffers, providing font-locking functionality among other things.
* Installation
** Emacs configuration
*** Installing SLIME
[[http://common-lisp.net/project/slime/][SLIME]] is required separately from swankr. To install slime,
perhaps the simplest is to pull the [[https://github.com/slime/slime][git sources]] into a
user-specific site directory, and arrange for that to be on the
emacs =load-path=; something like the following:
#+begin_src sh
mkdir -p ~/.emacs.d/site-lisp
cd ~/.emacs.d/site-lisp
git clone https://github.com/slime/slime.git
#+end_src
Following that, I have in my =~/.emacs= (you will need to adjust
paths to executables and source files):
#+begin_src emacs-lisp
;;; ~/.emacs.d/
(let ((default-directory (concat user-emacs-directory (convert-standard-filename "site-lisp/"))))
(normal-top-level-add-subdirs-to-load-path))
;;; SLIME
(require 'slime)
(setq slime-net-coding-system 'utf-8-unix)
(slime-setup '(slime-asdf slime-repl slime-scratch slime-presentations slime-media))
(setq slime-lisp-implementations
'((sbcl ("sbcl" "--dynamic-space-size" "2048" "--load" "/home/csr21/src/lisp/quicklisp/setup.lisp"))
(git-sbcl ("sh" "/home/csr21/src/lisp/sbcl/run-sbcl.sh" "--dynamic-space-size" "2048"))
(R ("R" "--no-save" "--max-vsize=4096M" "--interactive")
:init (lambda (port-filename coding-system)
(load "/home/csr21/src/R/swankr/swankr")
(format
"source('/home/csr21/src/R/swankr/swank.R', keep.source=TRUE, chdir=TRUE)\nstartSwank('%s')\n" port-filename)))))
(global-set-key (kbd "s-s") 'slime-selector)
#+end_src
*** Additional refinements
In addition, for keybindings like =C-c C-c= to work properly, emacs
needs to be told how to guess where a function definition begins.
This can be achieved with /e.g./
#+BEGIN_SRC emacs-lisp
(add-hook 'ess-mode-hook
(lambda ()
(setq defun-prompt-regexp "^\\(\\(\\sw\\|\\s_\\)+\\|\\s\"\\S\"+\\s\"\\)\\s-*\\(=\\|<-\\)\\s-*function\\s-*(.*)\\s-*")))
#+END_SRC
Fontification of quoted function names is suboptimal by default in
ESS; the following form in =~/.emacs= fixes that for ESS 5.11.
#+BEGIN_SRC emacs-lisp
(eval-after-load "ess-common"
(setq ess-R-mode-font-lock-keywords
(append
(list '("\\(\\sw\\|\\s_\\)+\\s-*\\(=\\|<-\\)\\s-*function"
1 font-lock-function-name-face t)
'("\\s\"\\(\\S\"+\\)\\s\"\\s-*\\(=\\|<-\\)\\s-*function"
1 font-lock-function-name-face t))
ess-R-mode-font-lock-keywords)))
#+END_SRC
*** Running
After performing the installation steps above, =M-- M-x slime RET R
RET= should start swank. You will be prompted to accept a version
mismatch -- simply accept -- then the SLIME REPL should start up,
giving a prompt. Enjoy!
* Development
swankr's primary development repository is a git repository,
accessible through
<http://common-lisp.net/r/users/crhodes/swankr.git> and
git://common-lisp.net/users/crhodes/swankr.git; a web view of the
development history is [[http://common-lisp.net/gitweb?p=users/crhodes/swankr.git][available through gitweb]]. You can also view
the current lists of [[file:BUGS.org]] and [[file:TODO.org]] items.
* Acknowledgments
Thanks to my colleagues at [[http://www.gold.ac.uk/][Goldsmiths, University of London]], for
suggesting that I investigate R for numerical and graphical
investigations, and to my colleagues at [[http://www.teclo.net/][Teclo Networks AG]] for giving
me motivation to get around to it. Initial development was done at
the [[http://ismir2010.ismir.net/][International Symposium on Music Information Retrieval]], which I
attended (indirectly) thanks to the EPSRC-funded [[http://www.omras2.org/][OMRAS2]] research
project and the [[http://www.londoninternational.ac.uk][University of London External System]]; Helmut Eller's
partial implementation of swank for Ruby was an excellent blueprint
to get development started.
* Footnotes
[fn:1] part of SLIME, the Superior Lisp Interaction Mode for Emacs:
<http://common-lisp.net/project/slime/>.
[fn:2] a free software environment for statistical computing and
graphics: <http://www.r-project.org/>.
[fn:3] also known as ESS, an emacs mode for interacting with a number
of statistical software packages, including R:
<http://ess.r-project.org/>.
* COMMENT:
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